Known in the art is a controlled current source (cf., for example, USSR Inventor's Certificate No. 591,996 published in Discoveries, Inventions, Industrial Designs and Trade Marks Bulletin, No. 5, 1978) comprising a choke and a capacitor whose reactive impedances are equal at the frequency of a voltage source, some outputs thereof are connected to two respective phases of the voltage source. The controlled current source also comprises a load current matching and adjusting unit which is a transformer having magnetic shunts, one output of the primary winding thereof being coupled to a third respective phase of the current source. Other outputs of the capacitor, choke and the primary winding of the transformer are joined in a star connection. Secondary windings of the transformer are coupled to the load, whereas a bias winding of the magnetic shunt, which is the control winding, is coupled to the source of constant voltage.
In this controlled current source the load current does not depend upon the load resistance. The load current is controlled in accordance with a specific program through adjusting the bias winding current.
The above controlled current source features a rather complicated magnetic system of the transformer, which results in greater bulk and cost of the current source and presents quite a problem for manufacturers.
Besides, this complicated magnetic system tends to increase the expenditure of conductor materials, add to the power consumed for control and narrow the range of load current control according to a specific program.